EP0052336B1 - Arrangement for packing elements - Google Patents

Description

The invention relates to a packing for installation in flow-through columns or tubes for the purpose of mass transfer. Technical areas of application are primarily rectification, absorption, mixing, heat transfer or particle and droplet separation. In the present case, it is a package that consists of a plurality of twisted strips that are layered parallel to one another in a rotationally symmetrical arrangement. Apparatus installations of this type are known from FR-A2 301 281 and EP-A-0 011 176. Although they have proven themselves quite well in practice, they have the disadvantage of relatively low mechanical stability when manufactured from fabric. As a result, the package is relatively easily deformed and thus damaged when it is installed or removed. Such damage is often not recognizable from the outside, so that it only becomes noticeable in operation in terms of a greatly reduced efficiency. In the known packs, the individual elements, i.e. the twisted strips (coils), either mechanically connected to one another with the aid of webs, strips or wires, or welded or soldered directly to one another at the points of contact of the strips. Such connections require a complicated and therefore complex manufacturing technology.

The invention has for its object to provide a pack that has a high mechanical stability, is easy to manufacture, and has a high level of process engineering.

In solving this problem, a package is assumed which consists of a plurality of twisted strips which are layered parallel to one another and which are arranged parallel to and rotationally symmetrical about an axis M. According to the invention, the strips are pleated, twisted in the same direction to form coils and the coils are arranged offset from one another in such a way that in four axisymmetric directions (Z1-Z4) their projections on the horizontal plane form an angle of 90 ° with one another and their angle αto the axis M by tan a =. j2 is defined, a group of continuous rectilinear channels are formed, where h is the pitch and b is the width of the spirals.

The spirals preferably all have the same pitch h and the same width b. When the helices are folded together, four points S meet at each pitch, at which the edges of four adjacent helices touch one another at one point. The starting material for the helices preferably consists of perforated strips or strips of woven material.

With regard to the pleating, optimal results are achieved if the pleating height corresponds to a tooth profile of the module 0.5 to 2.

Of particular interest is the geometry of the packing, which results from the arrangement of spirals according to the invention, resulting in a large number of ordered channels in axisymmetric directions. Such channels do not occur in the previously known spiral packs. These channels cause a high cross-mixing of the gas or vapor phase when exchanging substances between liquids and gases or liquids and vapors, and a high cross-mixing of the disperse phase in the case of extraction or mixing. A high degree of efficiency is achieved in this way. The channels are therefore essential for the advantageous effect of the invention. It is also surprising that without any mechanical connections between the coils (e.g. by soldering, welding or weaving) an extraordinarily high mechanical stability is achieved.

• Fig. einen Aufriss der Packung;
• Fig. 2 einen Schnitt AA gemäss Fig. 1 durch die Packung;
• Fig. 3 eine alternative Packungsgeometrie im Grundriss;
• Fig. 4 die Hauptrichtungen Z 1-4 der schrägliegenden Kanäle in der Packung;
• Fig. 5 eine Vorrichtung zur Herstellung eines plissierten Streifens und
• Fig. 6 den zu einer Wendel verdrillten plissierten Streifen.

The invention is explained below using exemplary embodiments. They show schematically:

• Fig. An elevation of the pack;
• FIG. 2 shows a section AA according to FIG. 1 through the pack;
• 3 shows an alternative packaging geometry in the plan;
• 4 shows the main directions Z 1-4 of the inclined channels in the pack;
• Fig. 5 shows a device for producing a pleated strip and
• 6 shows the pleated strip twisted into a helix.

1 and 2, the strips twisted into coils 1 are layered together in a rotationally symmetrical arrangement. Each coil 1 has four points of contact S with adjacent coils within a pitch h. Four spiral edges 2 intersect at each of these contact points S (see FIG. 2). With this arrangement, there are no points of contact between strip edges 2 and spiral axes (see FIG. 2). 6, pleated strips of sheet metal, fabric material or thermoplastics are used as the starting material for the strips twisted into Wendein 1. For the sake of illustration, the pleating is omitted in FIG. 1. It has surprisingly been found that the pleated coils 1 jam in their contact points S, which leads to a particularly stable packing and fixes the contact points S. Due to the high density of the packing geometry and the type and the large number of contact points S, there is an efficiency for the mass transfer between liquids and vapors which the previously known packs according to the prior art described at the outset do not achieve.

A large number of inclined channels 3 (see FIG. 7), the geometric position of which is shown in FIG. 4, are also characteristic of the new pack. The channels 3, which have an approximately crescent-shaped cross section, run parallel to the four axisymmetric directions Z1-Z4. Four sets of channels are thus formed in accordance with directions Z1-4, all channels within a set being parallel to one another. 4, the coils 1 which are layered parallel to the axis M of the pack are indicated in the upper left corner. The enveloping cylinder for the pack is labeled 4.

, wobei h die Ganghöhe und b die Breite der Wendel 1 bedeuten (s. Fig. 1). Projiziert man alle Kanäle 3 auf eine Horizontalebene(d.h. senkrecht zur Achse M),so ergibt sich also ein rechtwinkliges Gitter. Durch diese Relation und die oben angegebene Winkelbedingung ist die Packungsgeometrie eindeutig charakterisiert. Die Stärke der Verdrillung wird durch das Verhältnis charakterisiert. Vorzugsweise soll h/b in der Praxis zwischen 1 und 5 liegen (1<h/ b≦5). Dies bedeutet, dass die Richtungen der durchgehenden Kanäle zwischen a = 55° und a = 15° liegen (15≦α≦55°). Die oben angegebene Winkelbeziehung gilt natürlich nur für den Idealfall. Bei einer Verzerrung der regulären Anordnung, z.B. durch Deformation, können geringfügige Abweichungen auftreten.The intersection points of the directions Zl-4 which are decisive for the channels on the upper and lower circular surface of the cylindrical packing are designated P 1, P 2, P 3, P 4. The projections of the directions Z 1-Z 4 onto the horizontal plane form an angle of 90 ° with one another. The relationship tan applies to the angle a which the directions Z 1-4 form with the packing axis M.

, where h is the pitch and b is the width of the helix 1 (see FIG. 1). If all channels 3 are projected onto a horizontal plane (ie perpendicular to the axis M), a rectangular grid is obtained. The packaging geometry is uniquely characterized by this relation and the angular condition given above. The strength of the twist is characterized by the ratio. In practice, h / b should preferably be between 1 and 5 (1 <h / b ≦ 5). This means that the directions of the continuous channels are between a = 55 ° and a = 15 ° (15 ≦ α ≦ 55 °). The angular relationship given above of course only applies to the ideal case. If the regular arrangement is distorted, e.g. due to deformation, slight deviations can occur.

An alternative embodiment of the invention is shown in FIG. 3. Although the packing geometry differs considerably from that according to FIGS. 1 and 2, the inclined channels 3 also occur. The pack here consists of layers arranged parallel and congruently with one another with axially symmetrical spirals, which are offset by h / _{2 from} one another. For each pitch h there are six points of contact, in which two adjacent helixes touch each other with their edges. Overall, there are fewer points of contact than in the case of the pack according to FIGS. 1 and 2. The process engineering efficiency is thus also somewhat lower.

5 and 6 the pleating and twisting will be explained. 5, a metal strip 5 moves between two meshing gears 6 and 7. As a result, the strip 5 is pleated perpendicular to the transport direction and thus also perpendicular to the strip axis. The pleating height H _z , ie the amplitude of the corrugation, corresponds to the tooth profile of the gears 6 and 7. The best results were achieved with a pleating height H _z which corresponds to a tooth profile of the module 0.5 to 2. This results in a pleating of the uncoiled strip, which corresponds in profile to an equilateral triangle with an edge length of 1 to 3 mm. The helix 1 is produced by twisting the pleated strip 8. The pleating flattens somewhat towards the edge zones (see Fig. 6).

Due to the pleating and the position of the coils 1 with respect to one another (see FIGS. 1 and 2), a package of sheet metal coils already achieves a degree of wetting that other known packages only achieve through a complex and expensive fabric structure (braid or twill weave). When using a linen fabric, the packing according to the invention with a pleating according to the tooth module 1, a stripe width of 14 mm and a helix height of 25 mm resulted in a separation performance which is far above the above-mentioned packings according to the prior art.

Claims (5)

1. Packing for technical processes, consisting of a plurality of twisted strips stacked parallel to each other and arranged parallel to and in axial symmetry about an axis M, characterised in that the strips are pleated and twisted into spirals (1) of the same rotational sense and the spirals (1) are staggered in relation to each other so that groups of continuous channels (3) each extending in a straight line are formed in four axially symmetric directions Z 1-Z 4 whose projections on to a horizontal plane form an angle of 90° with each other and whose angle a with respect to the axis M is defined by tan α=b h · V2, where h is the pitch and b the width of the spirals (1).

2. Packing according to Claim 1, characterised in that the spirals (1) have the same pitch h and same width b and within each pitch h there are four points S at each one of which the edges (2) of four adjacent spirals (1) meet.

3. Packing according to Claims 1-2, characterised in that the spirals (1) are perforated.

4. Packing according to Claim 3, characterised in that the spirals (1) are made of a woven material.

5. Packing according to Claims 1-4, characterised in that the height H_z of the pleats corresponds to a tooth profile of modulus 0.5-2.

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